Is The Sugar In Fruit Bad For Your Bones?
Today’s article addresses a question frequently posed by Savers: does the sugar content of fruit outweigh the benefits of its bone-healthy nutrients and alkalizing effect? Sugar, if consumed in excess, leads to many health ailments, and it weakens bones. Most fruits contain high amounts of sugar, yet they are alkalizing Foundation Foods that offer bone-essential nutrients.
These sort of pros-vs-cons quandaries abound in health and nutrition – but there is a clear path forward. We can assess the impact of different fruits on blood sugar levels by looking at two measures: Glycemic Index (GI) and the more useful Glycemic Load (GL).
After a breakdown of what these two measures mean, we’ll look at the GI and GL values for a variety of fruits, and detail a plan of action to help you make the best choices for your body and your bones.
Why You Should Avoid Sugar
Refined white sugar– the kind found in processed foods and sweets– wreaks havoc on every system in your body: the brain, the digestive tract, the cardiovascular system, the immune system, and your bones. From your liver to your pancreas to your kidneys, too much sugar can lead to disease and dysfunction.
Sugar has a degenerative effect on your brain by promoting the formation of Advanced Glycation End products (AGEs). These sugar-bonded proteins weaken collagen, a major building block of the bone matrix, and build up in the brain, contributing to the beta-amyloid plaques and neurofibrillary tangles that contribute to Alzheimer’s disease.1
Sugar also cripples your ability to successfully break down and neutralize foreign matter like bacteria and pathogens, therefore weakening your immune system.2 It also competes with Vitamin C, utilizing the same pathways in and out of cells, effectively blocking this immune-supporting nutrient.
Most pressingly for Savers, sugar robs your bones of the minerals necessary for bone remodeling that keep bones resilient and young. Calcium, copper, and magnesium– all essential for the creation of new bone– are each impeded by sugar. 3,4,5
Considering how devastating sugar is to your body, sugary foods, especially processed foods, should be avoided. But what about fruits?
Fruits: Healthy Foods Or Sugary Temptation?
From cherries to watermelons, pineapples to pears, most fruits are classified as Foundation Foods in the Save Our Bones Program. That means they’re an essential part of maintaining a pH-balanced diet that provides your bones with the micronutrients they need to grow strong. Different fruits contain different beneficial compounds, but they’re bearers of antioxidants, flavonoids, potassium, vitamins, and minerals. Reams of research confirm that these phytonutrients, vitamins, and minerals increase bone density and improve overall health.6
Bear in mind that the sugar in fruits is composed of fructose and glucose, just like table sugar or sucrose, but the ratios differ slightly. For sucrose the ratio is 50/50, and for most fruits, it’s 40/55, but with some variations.
We also know that fruits are sweet. That makes them a welcome addition to the Saver’s diet, especially since the sugars in fruits are natural, which makes them far less of a problem than the refined sugars in processed foods. However, they still have an impact on our blood sugar levels. When we assess how sugary a fruit is, what we look at is this impact, which scientists measure in two related ways: Glycemic Index (GI) and Glycemic Load (GL).
Defining Glycemic Index
A food’s Glycemic Index is a number that describes how much that food will increase your blood sugar level. GI is based on a scale from 0 to 100, in which 100 is the blood sugar increase caused by consuming pure glucose. Food with a low GI (below 55) doesn’t have a significant impact on blood glucose levels, while food with a high GI (70 or above) will cause a sharp spike. Everything in the middle is considered an average score.
When you consume high-GI foods, they cause a drastic increase in blood glucose that quickly declines because of an insulin surge. In contrast, low-GI foods increase blood glucose more moderately, and the levels decrease much more gradually.
Glycemic Index is not always useful for determining the impact of the food on your plate. That’s because GI doesn’t consider typical portion sizes. It measures the blood sugar increase for a serving size that contains 50 grams of carbohydrates.
For some foods that might be far less than you would put on your plate, and for others, it might be more than you could eat in one sitting. You reach 50 grams of carbohydrates after just a few bites of a candy bar, but you’d have to eat five whole oranges to consume the quantity that their GI measures.
To address this problem, scientists at Harvard University devised a measurement that reflects typical serving sizes: Glycemic Load.
Defining Glycemic Load
The glycemic load is calculated directly from the glycemic index, but it also takes into consideration the amount of carbohydrates contained in a single serving. A certain food might have a high GI but a low GL if each serving doesn’t include many carbs.
Watermelon is a good example. It has a GI of 80, which is high, but the GI system bases that score on consuming 50 grams of watermelon-carbohydrates. A single serving of watermelon only contains 6 grams of available carbohydrate though, so unless you eat five servings at once, it doesn’t have a negative impact on your blood glucose levels.
The GL score is calculated by multiplying the GI by the grams of available carbohydrate per serving, then dividing by 100. If we follow the equation for watermelon, we multiply a GI of 80 by 6 (the grams of carbohydrate per serving) to get 480, then divide by 100 for a GL of 4.8.
GL scores of 10 or below are considered low. Scores of 11 to 19 are average, and anything above 19 is a high GL. Once you know the GL of the fruits in your diet, you can make informed decisions about the impact they have on your body, and moderate your consumption accordingly.7,8
A Handy Guide To The Glycemic Load Of Common Fruits
Use this table to find out the GL of these common fruits, pulled from studies of establishing the GL of a wide range of foods. The list is in descending order for glycemic load.
|Fruit||Glycemic Index||Serving Size (grams)||Glycemic Load (per serving)|
*Indicates Foundation Foods
Remember that these figures are for fresh, raw fruits unless otherwise noted. Dried fruit and fruit juices are far more sugary than fresh fruit, and have a much higher Glycemic Load.
Eat Your Way to Stronger Bones!
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As shown in the above table, many delicious alkalizing fruits have a low GL, so you can safely incorporate them into your pH-balanced diet. And remember that you can still eat fruits with the higher GL, but in moderation.
Till next time,
1Nobuyuki, Sasaki, et al. “Advanced Glycation End Products in Alzheimer’s Disease and Other Neurodegenerative Diseases.” The American Journal of Pathology. 1998 October; 153(4): 1149–1155. Web. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1853056/
2Sanchez, Albert J.L., et al. “Role of sugars in human neutrophilic phagocytosis.” The American Society for Clinical Nutrition. 1973 Nov; 26(11):1180-4. Web. http://ajcn.nutrition.org/content/26/11/1180.abstract%29
3Lawoyin, S., et al. “Bone mineral content in patients with calcium urolithiasis.” Metabolism 28:1250-1254.1979.
4Swaminathan, R. “Magnesium Metabolism and its Disorders.” The Clinical Biochemist Reviews. 2003 May; 24(2): 47-66. Web. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1855626/
5Wapnir, RA and Devas, G. “Copper deficiency: interaction with high-fructose and high-fat diets in rats.” The American Society for Clinical Nutrition, Inc. January 1995. Vol. 61 no. 1; 105-110. Web. http://ajcn.nutrition.org/content/61/1/105.abstract
6Rao, L.G.; Kang, N., and Rao, A.V. “Polyphenol Antioxidants and Bone Health: A Review.” Phytochemicals – A Global Perspective of Their Role in Nutrition and Health. Dr. Venketeshwer Rao (Ed.): ISBN: 978-953-51-0296-0. InTech. PDF. http://cdn.intechopen.com/pdfs-wm/32957.pdf
7Harvard University. Glycemic index and glycemic load for 100+ foods. Harvard Health Publishing. February, 2015. Web: https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods
8Atkinson FS, Foster-Powell K, Brand-Miller JC. “International Tables of Glycemic Index and Glycemic Load Values: 2008.” Diab
Care 2008; 31(12) Web. http://care.diabetesjournals.org/content/suppl/2008/09/18/dc08-1239.DC1/TableA1_1.pdf